The invention relates to a novel method and propellant composition for use in small and large caliber weapon ammunition to eliminate secondary muzzle flash without increasing production of smoke through incorporation of a microencapsulated coolant within a conventional double base extruded and ball propellants.
The invention further relates to an ammunition propellant composition and method whereby a coolant is added without reducing overall performance of the ammunition while reducing secondary muzzle flash without increasing smoke production.
The problems of smoke and muzzle flash have existed since the time small arm weapons have come into use. In most instances, the problems have been traced to one or more characteristics of the ammunition's propellant. In particular, muzzle flash may be divided into two phases, primary and secondary. Primary muzzle flash is due mainly to radiation of high energy gases as they leave the muzzle and produce a glow of short duration adjacent to the muzzle. Secondary flash is caused by oxidation of the combustible muzzle gases and is more objectionable since it produces a large flash of relatively long duration, beginning a short distance from the muzzle. This muzzle flash creates a problem of position disclosure, particularly at night, while muzzle smoke is objectionable because of daytime position disclosure.
Two methods are currently used to reduce secondary muzzle flash, namely the use of mechanical flash hiders on small arms weapons or the addition of chemical flash suppressants to standard ammunition propellant compositions. The use of mechanical flash hiders has not been satisfactory because they contribute to the weight of the weapon. Chemical flash suppressants used in small arms propellants consist of about one percent of potassium salts, i.e., sulfate or potassium nitrate as terminators for oxidative chain reactions, but are undesirable because they are the greatest single contribution to muzzle smoke.
Though muzzle smoke production is a function of many parameters, e.g., the oxygen balance of the propellants, ingredients, flame temperature, primer compositions and the like, the greatest single contributor is potassium. Thus prior art flash suppressants have only exacerbated the problem of position disclosure, as well as obscuring the gunner's vision.
The novel propellant composition of this invention containing a microencapsulated oxamide coolant has succeeded in passing through the flame zone intact, and has functioned in the gun barrel to cool the exiting gases so as to prevent muzzle flash without increased smoke production or interference with propellant burning behavior.
Moreover, the microencapsulated oxamide coolant of this invention has succeeded in providing a generic solution to the problem of muzzle flash for the new more energetic nitramine propellants, e.g., the cyclic nitramine propellant cyclo trimethylene trinitramine (RDX) and cyclo tetramethylene tetranitramine (HMX), which are characterized by a lower flame and a higher volumetric impulse than conventional nitroglycerine-nitrocellulose-triacetin ammunition propellants.